QAM and OFDM - An Analysis of their Noise and Multipath Immunity through Simulation

Faculty of Engineering, Electrical and Electronics Engineering Department, University of Khartoum, Sudan.
Periodicity:September - November'2012


In wireless communication systems, the transmitted signal is subject to different channel impairments, such as noise and multipath propagation. The demand for more reliable and higher speed wireless services has led to the development of digital communication techniques. This new development direction resulted in an increasing interest in new modulation formats that overcome the limitations associated with the wireless communication channel which degrades the performance of the communication system. The new sought modulation formats are expected to have high spectral efficiency and better immunity to transmission impairments. Of these modulation formats are the Quadrature Amplitude Modulation (QAM) and the Orthogonal Frequency Division Multiplexing (OFDM). This paper analyses through computer simulation the performance of: QAM, OFDM and QAM combined with OFDM under different channel impairments and compares which technique gives better performance under these conditions. The analysis was carried out using MATLAB and the results showed that QAM is used to effectively increase the channel capacity while OFDM is attractive because of its effective way in reducing the effect of inter-symbol interference (ISI). Furthermore a combination of these techniques has been proven to enhance the performance of a communication system.


Channel impairments, Multipath, QAM, OFDM, spectral efficiency, channel capacity ISI.

How to Cite this Article?

Eiman Mutwali Abdelmageed Hussain (2012). QAM and OFDM - An Analysis Of Their Noise And Multipath Immunity Through Simulation. i-manager’s Journal on Electronics Engineering, 3(1), 17-35.


[1]. T.S. Rappaport, (1996). Wireless communication. Upper Saddle River, N.J: Prentice Hall.
[2]. David Tse and Pramod Viswanath, (2005). Fundamentals of Wireless Communication. New York, USA: Cambridge University Press.
[3]. John Mills, (1917). Radio communication, theory and methods, with an appendix on transmission over wires. New York: McGraw-Hill Book Company.
[ 4 ] . Robert Frieden,B.A ., J.D ( 2 0 0 0 ) . "Telecommunications". Pennsylvania State University, International Relations , Motorola Satellite Communications, Inc.
[5]. Dipanwita Biswas, (2008). "Performance of Different M-ary modulation and Coherent Phase modulation over Wireless Fading channel," University of KIIT, India, M.A. Thesis.
[6]. Xiaodong Wang, (2004). Wireless Communication Systems. Upper Saddle River, N.J: Pearson Education Inc.,
[7]. Ian A., Glover and Peter M. Grant, (2004). Digital Communications, 2nd Edition. Cornwall, England: Pearson Prentice Hall.
[8]. Leon W. Couch, (2001). Digital and Analog Communication Systems, 6th Edition. Upper Saddle River, N.J: Prentice Hall.
[9]. Schulze Henrik and Christian Luders. (2005). Theory and Applications of OFDM and CDMA. John Wiley & Sons, Ltd.
[ 1 0 ] . M .Schwartz . ( 2 0 0 5 ) . Mobile Wireless Communications, 2nd edition. New York: Cambridge university press.
[11]. Ahmed R.S., Bahai and Burton R. Saltzberg (1999). Multi-Carrier Digital Communications: Theory and Applications of OFDM. [On-line] available at: [accessed 1 April 2011].
[12]. Ramjee Prasad, (2004). OFDM for Wireless Communications Systems. Norwood MA: USA, Artech House Inc.
[13]. Mohammad Safiqul Islam,Gouri Rani Barai, Atiq Mahmood, (2011). "Performance analysis of different modulation schemes using OFDM techniques in Rayleigh Fading channel". International Journal of Fundamental Physical Sciences, IJFPS, Vol.1, No.1, pp. 22-27, June.
[14]. Steven J. Vaughan-Nichols. (2002, November). Wi-Fi planet. [Online] availableat:http: // [accessed 15 August 2011].
[15]. Herve Benoit, (2006). Digital Television, Satellite, Cable, Terrestrial, IPTV, Mobile TV in the DVB Frame work, 3rd Edition, Paris: Focal Press.
[16]. Adnan Zafar and S. Zaineb Farooq, (2008). "Implementation and Analysis of QPSK &16-QAM Modulator & Demodulator,". ICAST 2nd International Conference on Advances in Space Technologies. Islamabad: Pakistan, 29th – 30th November.
[17]. B.P. Lathi, (2005). Linear systems and signals, 2nd ed. New York , USA: Oxford University Press.
[18]. Xiaolong Li, (2008). "Simulink-based Simulation of Quadrature Amplitude Modulation (QAM) System," in Proceedings of the IAJC - IJME International Conference, paper 205, ENG 105.
[19]. Parastoo Sadeghi. (2006). Lecture notes, topic: "Multicarrier Modulation and OFDM". Department of Information Engineering, Research School of Information Sciences and Engineering, the Australian National University, October.

Purchase Instant Access

Single Article

North Americas,UK,
Middle East,Europe
India Rest of world
Pdf 35 35 200 20
Online 35 35 200 15
Pdf & Online 35 35 400 25

If you have access to this article please login to view the article or kindly login to purchase the article
Options for accessing this content:
  • If you would like institutional access to this content, please recommend the title to your librarian.
    Library Recommendation Form
  • If you already have i-manager's user account: Login above and proceed to purchase the article.
  • New Users: Please register, then proceed to purchase the article.